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Research Article Free access | 10.1172/JCI118046

Cross-talk between calcium and cAMP-dependent intracellular signaling pathways. Implications for synergistic secretion in T84 colonic epithelial cells and rat pancreatic acinar cells.

M Vajanaphanich, C Schultz, R Y Tsien, A E Traynor-Kaplan, S J Pandol, and K E Barrett

Department of Medicine, University of California, School of Medicine, San Diego 92103, USA.

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Department of Medicine, University of California, School of Medicine, San Diego 92103, USA.

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Department of Medicine, University of California, School of Medicine, San Diego 92103, USA.

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Department of Medicine, University of California, School of Medicine, San Diego 92103, USA.

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Department of Medicine, University of California, School of Medicine, San Diego 92103, USA.

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Department of Medicine, University of California, School of Medicine, San Diego 92103, USA.

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Published July 1, 1995 - More info

Published in Volume 96, Issue 1 on July 1, 1995
J Clin Invest. 1995;96(1):386–393. https://doi.org/10.1172/JCI118046.
© 1995 The American Society for Clinical Investigation
Published July 1, 1995 - Version history
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Abstract

Treatment of various cells with combinations of agents that increase either cAMP or cytosolic calcium can lead to synergistic responses. This study examined interactions, or cross-talk, between these two intracellular messengers and its implication for signaling in two secretory cell types, T84 human colonic epithelial cells and rat pancreatic acinar cells. T84 cell chloride secretion was measured in Ussing chambers. Acinar cell activation was monitored as amylase secretion. Cytosolic calcium was assessed via fura-2 microfluorimetry. A cell-permeant analogue of cAMP synergistically enhanced secretory responses to calcium-mobilizing hormones in both cell types, but paradoxically reduced overall calcium mobilization. The reduction in calcium mobilization could be attributed to an inhibition of calcium influx in T84 cells, although a different mechanism likely operates in acinar cells. The effects of the cAMP analogue were reproduced by other agents that increase cAMP. Furthermore, econazole, an inhibitor of calcium influx, potentiated secretory responses to calcium-dependent stimulation in T84 cells without itself inducing secretion. We conclude that there is cross-talk between calcium and cAMP-dependent signaling pathways at the level of second messenger generation in two secretory cell types. This cross-talk appears to regulate the extent of secretory responses.

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